1. Technical Field
The present disclosure generally relates to the field of digital communication and, more particularly, to home networking with multiple-input and multiple-output capabilities.
2. Description of the Related Art
The g.hn standards (ITU-T G.9960, G.9961 and G.9963) use additional channel estimation (ACE) symbols for channel estimation. These symbols are typically modulated with uniform loading of two bits per sub-carrier using a pseudo-random sequence of bits that is known to the receiver. The current g.hn multiple-input multiple-output (MIMO) standard (G.9963), which is under development at the time of preparation of the present disclosure, supports a mode which uses precoding to enhance the capacity of links by reducing or eliminating cross-talk between the two transmission paths. In this mode, the preamble, header and ACE symbols are transmitted without precoding while the payload is transmitted with precoding. This ensures this mode can be used in a shared transmit opportunity (STXOP) where multiple nodes assigned to the STXOP that need to track the grid of time slots (TSs) are able to decode the header for virtual carrier sensing (i.e., keeping track of the grid simply by decoding the PHY frame header without having to decode complete frames).